Conventional techniques relating to such a load detection device include the techniques described in Patent Documents 1 and 2 cited below.
The diaphragm-type load detection sensor described in Patent Document 1 includes a fixed portion that is attached to an installation portion, a strain generating portion that includes, at the center of the fixed portion, a protruding weighted portion to which a load of an object to be detected is applied, and a strain gauge provided to the strain generating portion. The strain gauge is provided around substantially the entire circumference of the strain generating portion with a certain distance from the central axis of the weighted portion, and the fixed portion is fastened to the installation portion by using fixing screws.
The load sensor described in Patent Document 2 includes a base that has a hole at its center, that is deformed in response to a strain and on which a strain detection element is placed, and a sphere that is supported by the base and that serves as a load input portion.